This invention is related to a boiler system which is generally intended for providing steam power for propulsion of a ship, and more paticularly to a boiler system which is comprised of standardized, compact modules designed for quick and easy changeout and arranged to facilitate removal and replacement of any individual module.
Many Naval frigates are typically equipped with supercharged boilers which are vertically down-fired, natural-circulating units. The air is supplied from a supercharger to a windbox and divided equally among three burners which fire downward into a furnace. Fuel supplied by an oil pump is intimately mixed with the air and ignited. The products of combustion flow downward through the furnace across furnace screen tubes, across a superheater directly behind the furnace screen tubes and then across convection screen tubes located directly behind the superheater. The gas finally enters a pipe leading to a gas turbine which drives the supercharger. The furnace and convection screen tubes, and the superheater are integrally positioned within a single shell liner.
Due to the integrated design configuration of the boiler components of the prior art, severe limitations arise. For example, periodic repairs and overhauls are time consumming, costly and labor intensive, and must be performed in ship's fire rooms under adverse conditions; each boiler configuration, being nonstandard, results in a proliferation of spare parts, technical manuals, repair procedures and training. The output of existing boilers cannot be readily upgraded to supply increased quantities of steam to meet additional demands, and advanced technologies and materials cannot be readily backfit into existing ships or boilers because of space or configuration limitations.